A cementitious mixture refers to pastes, mortars, and concrete compositions comprising a hydraulic cement binder having consistencies ranging from stiff to extremely dry. Pastes are defined as mixtures composed of a hydraulic cement binder, either alone or in combination with pozzolans such as fly ash, silica fume, or blast furnace slag, and water. Mortars are defined as pastes that additionally include fine aggregate. Concretes additionally include coarse aggregate. These compositions may additionally include other admixtures such as set retarders, set accelerators, defoaming agents, air-entraining or air detraining agents, corrosion inhibitors, water reducing agents, and pigments.
Water repellant components have also been incorporated into conventional cement mixtures but the hydrophobic cementitious mixtures that are produced tend to exhibit reduced mechanical strengths. In addition, most hydrophobic agents are lipophilic organic solvents whereas the cement matrix is hydrophilic. The hydrophobic agents are insoluble in the water phase, causing inhomogeneous dispersion of the hydrophobic agent in aqueous cementitious mixtures. Industry is in need of developing improved hydrophobic cementitious mixtures using low-cost additives particularly from reclaimed waste materials.